Agreed - Maybe ST will shut up about people being able to change 17 flats in the time saved by not running Gatorskins for an IM.

Agreed - I have never owned a Gatorskin and probably never will.

Agreed - Tom A. really contributes a lot to the ST community.

I'm sure many of the owners of the new wheels were already planning on buying the force tires based on the article. if they don't see this buried in here on ST, then they'd never know about it. i feel like this should be a huge disclaimer somewhere in the article

I agree...and I apologize for overlooking that fact when I sent the combined data to Chris and Jon.

Chris? Jon? Sounds like a good edit to make on your blog post.

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I'm pretty sure that TomA rides the Specialized Cotton for a good reason.

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They're my "go to" tire on the road bike (on Hed Jet+ Blacks). They reside there for more than just aero+Crr reasons ;-)

On the TT bike (Flo 90 front and "wide" covered PT rim on back) I go with Conti SS23s. Then again, on the TT bike, I don't think my range of expected yaw angles is as large as what the Flo NDRV distribution assumes...

YMMV.

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Thanks again for doing all of this!

It seems this is the first time you tested Schwalbe Ones or published numbers from previous tests. When you originally tested the tubeless and standard clincher versions of their Ironman tires, there was a surprising dropoff between the brand new standard clincher IM and the tubeless specific IM with 335 miles on it. Something like the lightly used tubeless version being 4 watts per tire better at 40km/hr. Schwalbe says they use the same rubber, casing and construction between their IM and the previous generation Ones. The new Pro Ones are a little different.

Which version of the Ones did you test for this project?

As I discovered later, the difference between the tubeless and regular clincher Schwalbe IM tires was due to the fact that Schwalbe omits the under-tread puncture breaker layer on the tubeless versions. As it was eventually explained to me (after specifically ASKING at interbike) this is because they expect the tubeless riders to use sealant, so although that means the tubeless version is more likely to puncture, it also means they are relying on the sealant to take care of that. You can make your own evaluation of the validity of that approach...

The tire tested is the One model, not the Pro One.

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Have you found a correlation amongst tire weight and crr within a particular tire model?

Thanks Flo and Tom for a huge effort. Very good stuff.

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For the record A2 and it's big brother Aerodyne have a background story similar to what you are proposing. Aerodyne was created to meet the need of the NASCAR teams in the area and was bootstrapped & funded by the auto manufacturers to have local testing for their teams. Before Aerodyne most of the teams either used their manufacturers tunnels (located primarily in detroit), or lockheed down in Atlanta. A2 was created as a less expensive tunnel with the original use the lower rungs of the motorsports ladder (think late models), but that didn't pan out when the recession hit, so now it is used by cyclists.

To answer your real question though....tunnels are expensive, the equipment in them are expensive, the people knowledgeable enough to run them are rare and, you guessed it, expensive. This is a pretty fair market, there are more than a couple tunnels available all over the country and they charge what the market can bear. Aerodyne, the bigger tunnel, charges a fair amount more to test in and there is a waiting list to get in.

There is another tunnel in Mooresville/Concord area that is even more expensive, but the floor moves with the air and is a whole other story.

I typically don't weigh the tires, so I don't really know...

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Thanks for the quick and detailed reply.

I'm assuming you meant the standard clincher, not the tubeless specific one. In a post from a while ago, I talked about taking a video of puncturing a road tubeless tire (with sealant) at 90psi a dozen times with a thumbtack and having virtually no air loss as measured by the hand gauge. You made good points about the tire not being loaded or spinning. You then challenged me to jam a thumbtack into a latex tube and see if the same thing happened. Short story, you can patch latex tubes just like butyl tubes when they won't hold air after purposely popping them :-)

The crr of the (previous generation) One clincher seems to closely match your 2013 crr measurement of a 22 Schwalbe IM clincher at 0.0041. The tubeless version of the 22 Schwalbe IM (brand new) measured 0.0035 in your test. I'm really curious how the results would have looked if it were tubeless specific Ones used for the FLO test. Averaging your 30km/hr and 40km/hr columns and accounting for 1 tire instead of 2 would have me believe the removal of that puncture belt is worth 2-3 watts per tire in the low 20mph range. That would make a much more compelling case on the FLO charts since so much of it is based off crr. The new Pro One is supposed to be even better for crr too.

I feel that tubeless Schwalbe road tires make sense for instances where you want stable psi or are at risk of small punctures from things very similar to my thumbtack. I had Vittoria tubes that each lost 20psi during a ride. The newest tubeless tires don't appear to be giving up much to the cream of the crop 'fast' tires and hold PSI really well. I'm on my 3rd set of road tubeless tires with a 4th pair of 28s ready for my cx bike. I have had one full flat that whole time and it was because the rim tape failed. Dealing with the sealant while throwing a tube in wasn't fun, but it was far from the horror show that ST would make one believe fixing a flat on a tubeless tire would be.

Anyhow, I would still pick the Supersonic (If I can ever find them in stock) and latex tubes (without a patch) when every watt matters. I would probably ride my next IM bike split on well chosen Schwalbe tubeless tires again.

Actually, the tire tested was the One Tubeless version.

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Please excuse me while I pick myself off the ground and delete my previous posts.

I'm curious how the crr for the 23 One tubeless was so far off from the previous 22 IM tubeless roller test.

Only Schwalbe can answer that. Different tire construction, most likely...maybe they didn't omit the puncture breaker on that tubeless model?

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That playful Schwalbe...

"Oh no, those IM tubulars are all latex tubes. No wait, we changed to butyl without telling anybody and there's no way to know which is which."

"Yep, the IM and One are identical other than the 'aero' lines on the tread."

You can take a look here as some of the tires tested and weighed.
http://www.bicyclerollingresistance.com/

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It looks like Continental has taken the Black Chilly to most of the tires in their performance line. I wonder if some of the differences are due to a compound change during the time frame the tested tires were purchased. They are also selling version IIs of these tires. It is kind of funny how the Force 24 looks a lot like the GP4000s II 23 and the GP4000s II 25. Hmm.....

ProBikeKit is selling the IIs Attack & Force tires individually.

BTW: PBK has all of the Continentals on sale. I just ordered a pair of the Force for 42 ea. You can get 2 GP4000 23s for 38 ea.

I think you misunderstood. What I was saying is that if you had three different 23mm GP4000S IIs with one weighing X grams, the next being +20grams, and the last weighing +30grams they would end up rolling in that order, the theory being that a lighter tire means less tread which means a faster tire.

And thanks to Tom Ahnalt, this chart doesn't apply to me ;)

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Im curious as well. Sounds like rim width over brake track but what I didnt follow from Josh was 105% wider than tire At Least meaning more is better, no? And that Firecrest made up for that meaning if it was 102% that was hidden buy the rim but still At Least 105% was best.

And then is that for aerodynamics or for both rolling resistance and aerodynamics?

Say for example I have a choice between two tire sizes - 23 and 25. Which for argumets sake measure out at 25 and 28. Max rim width is 30. Both options are at least 105%. 23 tire obviouly even more but the 25 is going to have lower CRR. Which is the better option?

I just bought a new Force/Attack set to replace my 4000S tires, but, based on this data, it looks like it may make the most sense to stay with a 4000S on the front and put the Force on the rear. These will be on a HED Jet 9 front and HED Jet disc.

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Looks like even if using the 0.034 force, it still wouldn't hurt too much, result would still be faster than gp4000s? Gp4000s has the same 0.034 crr but less aero than force according to flo graph.
Unless I depict wrongly.

GPTT measures 1.2mm wider (on same rim) which is significant.

GPTT 23 is quite a bit fatter than an SS 23. It's more like a Force in size.

When Swiss Side tested it for aero, it was pretty bad, while a GP (not 4k, not TT) did much better. Seems like the grooves are generally good for aero on a large tire.

Well, we found Slowtwitch's ignorant post of the week

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